CAMP BUCCA, Iraq — Thousands of Iraqis held without charge by the United States on suspicion of links to insurgents or militants are being freed by this summer because there is little or no evidence against them.

Their release comes as the U.S. prepares to turn over its detention system to the fledgling Iraqi government by early 2010. In the six years since the war began, the military ultimately detained some 100,000 suspects, many of whom were picked up in U.S.-led raids during a raging, bloody insurgency that has since died down.

The effort to do justice for those wrongly held to begin with, some for years, also runs the risk of releasing extremists who could be a threat to fragile Iraqi security.

As part of an agreement between the two countries that took effect Jan. 1, Iraqi authorities have begun reviewing the cases of the detainees to decide whether to free them or press charges. About 13,300 remain behind barbed wire in U.S. custody in Iraq.

But Iraqi judges have issued detention orders to prosecute only 129 of the 2,120 cases they have finished reviewing so far this year — or about 6 percent, according to U.S. military data. As of Thursday, 1,991 detainees had been freed since Jan. 1.

An Associated Press reporter embedded for two days at Camp Bucca, the largest U.S. detention facility in Iraq, and talked with military officials about preparations to shut it down.

"God willing, God willing," said Layla Rasheed after learning that her son, a former government worker from Baghdad, was likely to be released. "He doesn't have anything to do with terrorists. I don't know why he was picked up."

The military also expects to release another 600 detainees by the end of March, a spokesman said.

Prosecute or releaseThe U.S. detention policy has been unpopular in a country where many feel that thousands have been detained without cause, and where the Abu Ghraib prison abuse scandal will be remembered for a long time.

Iraq's biggest Sunni parliamentary bloc has called for the release of virtually all detainees, arguing that even those who were militants no longer pose a threat because so many Sunni groups have abandoned the insurgency.

"It's very easy to go back and say, 'Well, you rounded up all these innocent people.' Well, innocence has different shades," Brig. Gen. David Quantock, commander of the U.S. detention system in Iraq, said in an interview this week.

"It's not like we have a choice — it is prosecute or release. So it's a huge undertaking right now to try to find as much evidence as we can. We're not going after all of them, we're going after a certain amount."

It is not clear that Iraqi judges will continue to issue warrants in so few cases.

Those who have been freed since Jan. 1 make up what Quantock called low-level threats that Iraqi security forces should be able to contain if they return to insurgent groups. Extremists will be the last to have their cases reviewed, giving the U.S. time to compile evidence against what they consider the highest risk to Iraq's security.

Starting overQuantock cited the cases of about 3,000 detainees where U.S. officials are scrambling to compile enough evidence to keep them locked up. Additionally, 2,400 detainees have already been convicted or are awaiting trial, a military spokesman said.

Most of the detainees — about 9,600 — are being held at Camp Bucca, a sprawling, dusty military facility that sits a few yards north of the Kuwaiti border, about 340 miles southeast of Baghdad. It is slated to close this summer.

Its detainees included those whom Quantock called "the worst of the worst" — suspected al-Qaida terrorists, Shiite militants and Sunni insurgents.

And there are those like Sunni teacher Suhail Najim Abdullah, who was released from Camp Bucca in March 2008 after being held there for more than three years.

"They just simply apologized to me and said, 'You have been arrested mistakenly,'" Abdullah said in an interview in Baghdad this week. "They gave me a shirt and trousers and $20. It's like I started my life over from zero."

Claims of tortureAbdullah is suing two private U.S. security contractor firms that he said tortured him for a month while being detained at Abu Ghraib in 2003. A U.S. military spokesman confirmed Abdullah's detention at Bucca but did not provide details about his time at Abu Ghraib.

International law allows the capture and detention of people who are considered an "imperative" national security threat during times of war or conflict. However, human-rights groups like Amnesty International have argued that the United States violated detainees' legal rights by holding them without charge after Iraq was declared a sovereign nation in June 2004.

That argument largely became moot with the Jan. 1 agreement. The U.S. currently is referring up to 1,500 detainees cases to Iraqis each month for review.

Human-rights groups worry about the detainees who will remain in Iraqi custody.

"We have concerns for those who would be transferred to Iraqi custody because of allegations of torture," said Nicole Choueiry of Amnesty International in London. The Jan. 1 security agreement, Choueiry said, "does not contain any guarantees for their safety."

Test caseAt Camp Bucca, Quantock said 75 percent of detainees are Sunni and nearly all the rest are Shiite. Nearly all are Iraqi: Only 137 detainees come from 22 other counties, most from Egypt, Syria, Jordan and Iran.

Quantock said very few detainees who have been released are later recaptured: Out of 18,600 who were freed last year, only 157 returned.

How much of a threat — if any — the detainees will pose once freed is unclear.

A potential danger, said one U.S. official, is whether hard-core foreign fighters would head to Western Europe or the United States to carry out attacks there.

One Camp Bucca imam said the majority of detainees are ready to forgive once they are released — even if they are angry and confused after being held so long.

"Some of them have decided to go outside Iraq to change," said the imam, who identified himself only as Sheik Abdul-Sattar. "Some can say, we can forgive everyone. The majority are like that. The extremists speak of revenge."

The camp also is being closely watched as a test case as the Obama administration grapples with releasing detainees or expanding legal rights to those held at Guantanamo Bay in Cuba and Bagram Air Base in Afghanistan.

"It's a unique time in the history of warfare, with all of the confusion and the chaos surrounding what to do with detainees, to watch and see if it works," said Glenn Sulmasy, a professor of international law and national security expert at the U.S. Coast Guard Academy. "We don't know. And we're going to be dealing with these same issues at Guantanamo and Bagram in the future."

Copyright 2009 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.